greenplumn decompress_reader 代码
文件路径：/gpcontrib/gpcloud/include/decompress_reader.h
#ifndef INCLUDE_DECOMPRESS_READER_H_
#define INCLUDE_DECOMPRESS_READER_H_
#include "reader.h"
#include "s3common_headers.h"
#include "s3exception.h"
#include "s3macros.h"
#include "s3params.h"
/ 2MB by default
extern uint64_t S3_ZIP_DECOMPRESS_CHUNKSIZE;
class DecompressReader : public Reader {
public:
DecompressReader();
virtual ~DecompressReader();
virtual void open(const S3Params ¶ms);
/ read() attempts to read up to count bytes into the buffer.
/ Return 0 if EOF. Throw exception if encounters errors.
virtual uint64_t read(char *buf, uint64_t count);
/ This should be reentrant, has no side effects when called multiple times.
virtual void close();
void setReader(Reader *reader);
void resizeDecompressReaderBuffer(uint64_t size);
private:
void decompress();
uint64_t getDecompressedBytesNum() {
return S3_ZIP_DECOMPRESS_CHUNKSIZE - this->zstream.avail_out;
}
Reader *reader;
/ zlib related variables.
z_stream zstream;
char *in; / Input buffer for decompression.
char *out; / Output buffer for decompression.
uint64_t outOffset; / Next position to read in out buffer.
bool isClosed;
};
#endif /* INCLUDE_DECOMPRESS_READER_H_ */